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Abstract:

Disclosed herein are an apparatus and method for capturing stereographic
images. The apparatus includes two cameras, a screen unit, and a
processing unit. The two cameras capture left and right images,
respectively. The screen unit receives a matching region between the left
and right images from a user. The processing unit corrects errors
corresponding to the two cameras based on the matching region, and
captures a stereographic image.

Claims:

1. An apparatus for capturing stereographic images, the apparatus
comprising: two cameras for capturing left and right images,
respectively; a screen unit for receiving a matching region between the
left and right images from a user; and a processing unit for correcting
errors corresponding to the two cameras based on the matching region, and
capturing a stereographic image.

2. The apparatus as set forth in claim 1, wherein the processing unit
comprises: an input unit for receiving the matching region; a point
search unit for searching the matching region for a matching point; a
determination unit for determining whether the matching point is correct
using a preset determination procedure; a calibration unit for generating
camera parameters by performing a camera calibration operation if as
a result of the determination, it is determined the matching point is
correct; and a correction unit for correcting errors in positions of the
two cameras based on the camera parameters.

3. The apparatus as set forth in claim 2, wherein the point search unit
searches for the matching point by applying a matching algorithm to the
matching region.

4. The apparatus as set forth in claim 2, wherein if, as a result of the
determination, it is determined that the matching point is not correct,
the left and right images are enlarged and provided to the user using the
screen unit, and a matching region selected by the user another time is
received.

5. The apparatus as set forth in claim 1, wherein the screen unit
corresponds to a touch screen for providing the matching region so that
the user can select the matching region.

6. The apparatus as set forth in claim 1, further comprising a camera
control unit for controlling positions of the two cameras.

7. The apparatus as set forth in claim 1, further comprising an output
unit for providing the stereographic image to the user.

8. A method of capturing stereographic images using two cameras, the
method comprising: receiving left and right images from the two cameras;
receiving a matching region between the left and right images from a
user; and correcting errors, corresponding to the two cameras, based on
the matching region, and capturing a stereographic image.

9. The method as set forth in claim 8, wherein the capturing comprises:
searching the matching region for a matching point; determining whether
the matching point is correct using a preset determination procedure; if,
as a result of the determination, it is determined that the matching
point is correct, generating camera parameters by performing a camera
calibration operation; and correcting errors in positions of the two
cameras based on the camera parameters.

10. The method as set forth in claim 9, wherein the searching comprises
searching for the matching point by applying a presetmatching algorithm
to the matching region.

11. The method as set forth in claim 9, further comprising, if, as a
result of the determination, it is determined that the matching point is
not correct: enlarging the left image and the right image, and providing
the enlarged images to the user; and receiving a matching region between
the left image and the right image, which was selected by the user
another time.

12. The method as set forth in claim 8, wherein the receiving a matching
region comprises providing the left and right images to the user using a
touch screen and receiving the matching region selected by the user.

Description:

CROSS REFERENCE TO RELATED APPLICATION

[0001] This application claims the benefit of Korean Patent Application
No. 10-2010-0131560, filed Dec. 21, 2010, which is hereby incorporated by
reference in its entirety into this application.

BACKGROUND OF THE INVENTION

[0002] 1. Technical Field

[0003] The present invention relates generally to an apparatus and method
for capturing stereographic images and, more particularly, to an
apparatus and method for capturing stereographic images using two
cameras.

[0004] 2. Description of the Related Art

[0005] A method of capturing stereographic images is a technique of
capturing stereographic images using cameras so that users can naturally
perceive the stereographic images, based on an analysis of the process by
which humans sense stereographic images. The apparatus for capturing
stereographic images uses two cameras as a human uses two eyes. In this
case, there is a need for devices that fasten the two cameras.
Furthermore, dizziness-free images can be acquired only when the pieces
of information of the two cameras are accurately consistent with each
other.

[0006] In general, the apparatus for capturing stereographic images
includes two cameras, rigs corresponding to fastening devices, and a
capturing device for checking captured images. The most important points
to be considered when a stereographic image is captured are the removal
of errors from the images acquired by the two cameras and the
minimization of the possibility of causing dizziness. If the positions of
the two cameras are fixed using the rigs, the vertical and horizontal
errors in the images should be minimized and the optical characteristics
of the two cameras should be matched with each other.

[0007] In the prior art, the vertical and horizontal errors in the two
images, the distortion, and the differences in the characteristics of the
cameras can be known by analyzing the two images, acquired by the two
cameras, in real time using additional hardware. Here, the additional
hardware is an expensive specialized device that can process two sheets
of High-Definition (HD) images at the same time. Accordingly, there is a
need for a method which may be easily used at places where stereographic
image capturing is applied and which can process images in real time even
using an ordinary inexpensive device.

[0008] In order to match the pieces of information of two cameras with
each other, the camera calibration process is the most important thing.
The calibration process enables the accurate positions of the two cameras
to be determined, thereby overcoming errors that may occur while a
stereoscopic image is captured.

[0009] In general, a preset pattern is used in the calibration process.
Here, the most widely used type of pattern includes a checkerboard, and
the type of pattern may vary depending on the calibration method. At the
site of actual capturing, however, it is difficult to carry a large
checkerboard, and it is inconvenient to stand the board up when setting
the capturing settings. Accordingly, the checkerboard is rarely used.
Furthermore, it is difficult to use the checkerboard because the
capturing setting time takes too long.

SUMMARY OF THE INVENTION

[0010] Accordingly, the present invention has been made keeping in mind
the above problems occurring in the prior art, and an object of the
present invention is to provide an apparatus and method for capturing
stereographic images using two cameras.

[0011] In order to accomplish the above object, the present invention
provides an apparatus for capturing stereographic images, the apparatus
including two cameras for capturing left and right images, respectively;
a screen unit for receiving a matching region between the left and right
images from a user; and a processing unit for correcting errors
corresponding to the two cameras based on the matching region, and
capturing a stereographic image.

[0012] The processing unit may include an input unit for receiving the
matching region; a point search unit for searching the matching region
for a matching point; a determination unit for determining whether the
matching point is correct using a preset determination procedure; a
calibration unit for generating camera parameters by performing a camera
calibration operation if, as a result of the determination, it is
determined the matching point is correct; and a correction unit for
correcting errors in positions of the two cameras based on the camera
parameters.

[0013] The point search unit may search for the matching point by applying
a matching algorithm to the matching region.

[0014] If, as a result of the determination, it is determined that the
matching point is not correct, the left and right images may be enlarged
and provided to the user using the screen unit, and a matching region
selected by the user another time may be received.

[0015] The screen unit may correspond to a touch screen for providing the
matching region so that the user can select the matching region.

[0016] The apparatus may further include a camera control unit for
controlling positions of the two cameras.

[0017] The apparatus may further include an output unit for providing the
stereographic image to the user.

[0018] In order to accomplish the above object, the present invention
provides a method of capturing stereographic images using two cameras,
the method including receiving left and right images from the two
cameras; receiving a matching region between the left image and the right
image from a user; and correcting errors, corresponding to the two
cameras, based on the matching region, and capturing a stereographic
image.

[0019] The capturing may include searching the matching region for a
matching point; determining whether the matching point is correct using a
preset determination procedure; if, as a result of the determination, it
is determined that the matching point is correct, generating camera
parameters by performing a camera calibration operation; and correcting
errors in positions of the two cameras based on the camera parameters.

[0020] The searching may include searching for the matching point by
applying a preset matching algorithm to the matching region.

[0021] The method may further include, if, as a result of the
determination, it is determined that the matching point is not correct,
enlarging the left image and the right image, and providing the enlarged
images to the user; and receiving a matching region between the left
image and the right image, which was selected by the user another time.

[0022] The receiving a matching region may include providing the left and
right images to the user using a touch screen and receiving the matching
region selected by the user.

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The above and other objects, features and advantages of the present
invention will be more clearly understood from the following detailed
description taken in conjunction with the accompanying drawings, in
which:

[0024] FIG. 1 schematically shows the construction of an apparatus for
capturing stereographic images according to an embodiment of the present
invention;

[0025] FIG. 2 shows the construction of a processing unit according to an
embodiment of the present invention;

[0026]FIG. 3 is a diagram showing an example in which a screen unit is
used according to an embodiment of the present invention; and

[0027] FIG. 4 is a flowchart illustrating a method of capturing
stereographic images according to an embodiment of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0028] Reference now should be made to the drawings throughout which the
same reference numerals are used to designate the same or similar
components.

[0029] The present invention will be described in detail below with
reference to the accompanying drawings. Repetitive descriptions and
descriptions of known functions and constructions which have been deemed
to make the gist of the present invention unnecessarily vague will be
omitted below. The embodiments of the present invention are provided in
order to fully describe the present invention to a person having ordinary
skill in the art. Accordingly, the shapes, sizes, etc. of elements in the
drawings may be exaggerated to make the description clear.

[0030] An apparatus and method for capturing stereographic images
according to embodiments of the present invention will be described in
detail below with reference to the accompanying drawings.

[0031] FIG. 1 schematically shows the construction of an apparatus for
capturing stereographic images according to an embodiment of the present
invention.

[0032] Referring to FIG. 1, the apparatus for capturing stereographic
images includes two cameras 110 and 120, a camera control unit 150, a
processing unit 200, a screen unit 300, and an output unit 400. Although
the apparatus for capturing stereographic images according to the
embodiment of the present invention are illustrated as including the two
cameras 110 and 120, the camera control unit 150, and the screen unit 300
as described above, the two cameras, the camera control unit and the
screen unit may be externally provided and operate in conjunction with
the other components.

[0033] The two cameras 110 and 120 capture left and right images of a
corresponding area, respectively.

[0034] The camera control unit 150 corresponds to rigs that control the
positions of the two cameras 110 and 120.

[0035] The processing unit 200 captures a stereographic image by
correcting the positions of the two cameras 110 and 120 and an error
corresponding to the camera control unit 150 used to control the two
cameras 110 and 120, based on a matching region corresponding to the left
and right images received from the two cameras 110 and 120.

[0036] The screen unit 300 corresponds to a touch screen, and receives the
matching region of the left and right images acquired by the two cameras
110 and 120 from a user. Next, the screen unit 300 transfers the selected
matching region to the processing unit 200.

[0037] The screen unit 300 according to the embodiment of the present
invention provides the function of enabling a user to freely enlarge or
reduce an image. Accordingly, a user can easily select a matching region
or matching pixels included in the matching region.

[0038] The output unit 400 provides a user with a stereographic image
captured by the processing unit 200.

[0039] The processing unit 200 will now be described in detail with
reference to FIG. 2.

[0040] FIG. 2 shows the construction of the processing unit 200 according
to an embodiment of the present invention.

[0041] Referring to FIG. 2, the processing unit 200 includes an input unit
210, a point search unit 220, a determination unit 230, a calibration
unit 240, and a correction unit 250.

[0042] The input unit 210 receives a matching region between a left image
and a right image. Here, the input unit 210 manually receives a matching
region between the two images via the screen unit 300.

[0043] The point search unit 220 searches the matching region for a
matching point. Here, the point search unit 220 may search for the
matching point by applying a matching algorithm to the matching region,
but the present invention is not limited thereto.

[0044] When a matching point is searched for by automatically searching
left and right images, real-time processing is difficult because both the
left and right images should be analyzed. In contrast, when the matching
algorithm is applied to the matching region according to an embodiment of
the present invention, the matching algorithm is applied to an image
corresponding to the matching region, not both the left image and the
right image. Accordingly, the size of an image is reduced, and therefore
real-time processing is possible.

[0045] The determination unit 230 determines whether the retrieved
matching point is correct using a preset determination procedure.

[0046] The calibration unit 240 generates camera parameters by performing
a camera calibration operation on the matching point. Here, the camera
calibration operation is the process of generating camera parameters
(i.e., a specific standard) by adjusting the matching point in accordance
with the characteristics and properties of the two cameras 110 and 120.

[0047] Although the calibration unit 240 according to an embodiment of the
present invention has been described as generating camera parameters
using the camera calibration operation, it may generate camera parameters
using rig convergence, an Inter Ocular Distance (IOD) between cameras,
and zoom control.

[0048] The correction unit 250 corrects errors in the positions of the two
cameras 110 and 120 and control information related to the control of the
camera control unit 150 based on the camera parameters.

[0049] The screen unit 300 will now be described in detail with reference
to FIG. 3.

[0050]FIG. 3 is a diagram showing an example in which the screen unit 300
is used according to an embodiment of the present invention.

[0051] Referring to FIG. 3, the screen unit 300 provides a left image and
a right image to a user, and receives at least one matching region from
the user.

[0052] Thereafter, the processing unit 200 searches the matching region
for a matching point, and may output a result on the screen unit 300. If
the output result is not correct or erroneous, the user may enlarge the
matching region and manually input the matching point using the screen
unit 300.

[0053] A method of capturing stereographic images will be described in
detail below with reference to FIG. 4.

[0054] FIG. 4 is a flowchart illustrating the method of capturing
stereographic images according to an embodiment of the present invention.

[0055] First, the apparatus for capturing stereographic images according
to the embodiment of the present invention operates in conjunction with
the two cameras 110 and 120, the camera control unit 150, and the screen
unit 300.

[0056] Referring to FIG. 4, the apparatus for capturing stereographic
images sets the two cameras 110 and 120, the camera control unit 150 and
the screen unit 300 at a place where a stereographic image will be
captured at step S401.

[0057] The apparatus for capturing stereographic images receives a left
image and a right image from the two cameras 110 and 120 at step S402.

[0058] The apparatus for capturing stereographic images outputs the left
image and the right image to a user using the screen unit 300 at step
S403. Here, the screen unit 300 corresponds to a touch screen.

[0059] The apparatus for capturing stereographic images receives a
matching region, selected by the user, from the screen unit 300 at step
S404. Here, the matching region corresponds to a region where the left
image and the right image acquired by the two cameras 110 and 120 have
been matched to each other.

[0060] The apparatus for capturing stereographic images searches the
matching region for a matching point at step S405. Here, the apparatus
for capturing stereographic images may search for the matching point by
applying a specific matching algorithm to the matching region.

[0061] The apparatus for capturing stereographic images determines whether
the retrieved matching point is correct using a preset determination
procedure at step S406.

[0062] If as a result of the determination, it is determined that the
matching point is not correct, the apparatus for capturing stereographic
images enlarges the left and right images and provides the enlarged
images to the user using the screen unit 300. Here, the screen unit 300
provides the user with a matching region or matching pixels which are
more detailed than the matching region. Accordingly, the user selects the
matching region again. This process is repeated until a correct matching
point is retrieved.

[0063] If as a result of the determination, it is determined that the
matching point is correct, the apparatus for capturing stereographic
images generates camera parameters by performing a camera calibration
operation on the matching point at step S407.

[0064] The apparatus for capturing stereographic images corrects errors in
the positions of the two cameras 110 and 120 and control information
related to the control of the camera control unit 150 based on the camera
parameters and then captures a stereographic image at step S408.

[0065] The apparatus for capturing stereographic images according to the
embodiment of the present invention calculates the accurate positions of
cameras by performing calibration on the cameras in real time, and
minimizes vertical and horizontal errors by correcting errors in the
rigs. Accordingly, a high-quality stereographic image can be captured.
Here, the apparatus for capturing stereographic images can easily receive
input from a user using a touch screen, and set the camera settings
corresponding to the input in real time. Accordingly, there is a high
possibility that the apparatus of the present invention will be used in a
capturing place.

[0066] Furthermore, if calibration is automatically performed because a
subject is continuously changed in a place where a pattern is not used,
there are problems in that a lot of errors are generated and the time
taken to correct the errors is long. However, the present invention can
reduce the generation of the errors and perform calculations accurately.
Accordingly, a high-quality image can be acquired.

[0067] As described above, according to the embodiments of the present
invention, the apparatus and method for capturing stereographic images
can accurately perform calibration in real time using common pieces of
equipment (e.g., cameras, rigs, and a touch screen).

[0068] Furthermore, according to the embodiments of the present invention,
the apparatus and method for capturing stereographic images can obtain
high-quality stereographic images using the properties of cameras, rigs,
and a touch screen.

[0069] Although the preferred embodiments of the present invention have
been disclosed for illustrative purposes, those skilled in the art will
appreciate that various modifications, additions and substitutions are
possible, without departing from the scope and spirit of the invention as
disclosed in the accompanying claims.

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Patent applications by Seung Woo Nam, Daejeon KR

Patent applications by Yun Ji Ban, Daejeon KR

Patent applications by Electronics and Telecommunications Research Institute